Findings in the first cohort of 100 patients, after careful rediagnosis, show unipolars more vulnerable to dyskinesia, in terms of months on antipsychotics before TD, total months since first antipsychotic therapy, and grams of antipsychotic taken, than schizophrenic or schizoaffective patients. Bipolars develop dyskinesia after fewer months on antipsychotics than schizophrenics or schizoaffectives. Most patient show slow improvement in TD over years. Patients off antipsychotics do best. Lithium use is not associated with slower onset of TD, while antiparkinson drug use is. Analyses of risk factors asociated with the course of dyskinesia in the first cohort have just begun. Funds are requested to permit completion of data collection, entry and analysis for the second cohort, to see whether findings from the first cohort can be replicated, and the completion of manuscripts reporting findings. In addition, special effort will be given to examining additional risk factors based on focussed chart review for patients in both cohorts. These include early and also persistent extra-pyramidal side effects, alcoholism and substance abuse, family history of affective illness, adequacy of clinical response to antipsychotic drugs and patterns of affective symptomatology in schizophrenic and schizoaffctive patients.